An essential element of all aerators is a jet-forming means provided within a casing from which a plurality of relatively fine jets of liquid, such as water, are discharged into a mixing chamber to be fragmented and mixed intimately with air, after which straightening means operate to cause a coherent stream of aerated liquid to be discharged from the aerator. The jet-forming means have typically been in the form of a perforated disc or the equivalent.
When usage of aerators disclosed the fact that the disc perforations tended to clog with water-borne debris, a self-cleaning aerator was developed in which the jet-defining flow apertures of a metal disc, or equivalent, were provided by two mating metal parts that were resiliently separble, during the non-flow condition, to permit debris to be flushed between the separated edges of the two parts before water pressure of the steady flow condition operated to restore the two parts to their mating condition. Such prior art constructions are disclosed in U.S. Pat. Nos. 2,707,624; 2,896,863; 2,928,607; and 3,014,665.
The use of plastic apertured discs in aerators has operated to reduce the cost of the aerator. But the use of plastic parts to define jet-forming flow apertures did not permit effective use of the same self-cleaning feature as first disclosed in U.S. Pat. No. 2,707,624. It has been the experience that jet-defining flow apertures preferably be provided in their entirety in a single part, and should not be defined between edges of two mating parts.
One of the most effective designs of an aerator using plastic internal parts is disclosed in U.S. Pat. No. 3,684,191 wherein one internal part is in the form of an annular guide ring, and a second internal part, made wholly of plastic, is in the form of a flanged, cup-shaped, plug member with a series of fine vertical jet-forming slots defined therethrough. The fine vertical slots in the plug member are susceptible of being clogged by water-borne debris.
It is, therefore, one object of this invention to provide self-cleaning character for an aerator whose jet-forming apertures are defined in a molded plastic part, whereby water-borne debris may be automatically flushed from the aerator without disassembly of the aerator, or removal of the aerator from its operative environs.
It is another object of this invention to provide a self-cleaning aerator wherein the liquid flow therethrough is automatically controlled to effect, upon initial liquid flow, an increased and directed liquid velocity therethrough to effect a directed scrubbing, and debris dislodging, flow action over the jet-forming apertures, after which a steady state condition, for which the aerator is designed, will be established.
A further object of this invention is to provide a self-cleaning aerator that is characterized by economy of construction and effectiveness of operation.
Further objects and advantages will become apparent to one skilled in the art from the following description of preferred embodiments of the invention.